Research On Design, Fabrication, Detection And Application Of Microfluidic Biochips For Stem Cells

Stem cells are essential for cell therapy, regenerative medicine and cancerresearch, which are well known. However, there are also problems to be solved inethics and morals, differentiation potency, immunological rejection and safety. Themechanism study of stem cells, which are important for controlling proliferation anddifferentiation, reducing immune rejection and avoiding tumorigenesis, has drawnmore and more attention. Microfluidic chips with its unique advantages could beemployed to control proliferation and differentiation of stem cells in amicroenvironment, which makes microfluidic chips one of the irreplaceable tools inmechanism studies of stem cells. The research of stem cells in microfluidic chips hasjust started currently. The references in this field are still less. Moreover, there are notstandard, efficient and stable methods to control and culture stem cells in microfluidicchips. This paper attempts to explore the methods of controlling and culturing stemcells in homemade microfluidic chips.In this paper, the design, fabrication and application of microfluidic chips forstem cells are researched. The problems of stem cells’ breathing, shear force’sinfluence, microfluidic chips’ material selecting, microfluidic chips’ productivity, costand usability, stem cells’ microinjection and culturing are explored.In the respects of designing microfluidic chips,7basic conditions of culturingstem cells in culture dishes were analyzed. In addition, the methods of realizing7basic conditions in microfluidic chips were analyzed. Based on the analysis,microfluidic chips are designed. Moreover, the air chambers and the culture chambersin microfluidic chips are optimized by finite element method. Results show: when thedistance between the entrance and exit of gas chamber increases, the percentage ofportion with smaller velocity reduces, the percentage of portion with greater velocityincreases, the velocity of changing air increases and the residue of air becomes less,which has nothing to do with the structures of the entrance, the exit and gas chamber;and in microfluidic chips driven by electric micro injection device, when the diameterof culture chamber is1mm more or less, the shear force suffered by stem cells isabout10-2dynes/cm2which has no influence to the stem cells.In the respects of fabricating microfluidic chips, the material, methods andprocesses of fabricating microfluidic chips are introduced. Some important problems in fabricating microfluidic chips are analyzed: the selection of microfluidic chips’material, the productivity and cost of fabricating microfluidic chips and the usabilityof microfluidic chips. In the processing cover slips, CD/DVD manufacturingtechnology is adopted. In the bonding of cover slips and substrates, the thermalbonding method is adopted. In the packaging of microfluidic chips, the micro needlesare adopted. Meanwhile, the productivity of processing, bonding and packaging isestimated. Results show: the material PC is suited for fabricating microfluidic chips;repeated bonding could increase the productivity and reduce the cost of fabricatingmicrofluidic chips; and using micro needles could make the usability of microfluidicchips easier.In the respects of applying microfluidic chips, ICR mouse bone marrowmesenchymal stem cells were chosen as the experimental cells and low temperaturesteam sterilization was chosen as the microfluidic chips’ sterilization methods. Inaddition, a manual injection device was designed and made. Using the manualmicroinjection device and an electric microinjection device, a single cell and cellswere microinjected into microfluidic chips. Moreover, the flow velocity inmicrofluidic chips was measured to confirm the optimized results. After themicroinjection and measurement, single cells and cells were cultured in microfluidicchips. Results show: the movement velocity of a single cell is similar to the liquidflow velocity which means the optimized results and the real situation reach a goodagreement; the limited culture area in microfluidic chips may inhibit the proliferationrate of ICR mouse bone marrow mesenchymal stem cells; and the inhibition orpromotion of proliferation rate may relate to the kinds of cells.